Retinoblastoma and simulating lesions - Role of CT, MR imaging and use of Gd-DTPA contrast enhancement

Retinoblastoma, the most common intraocular tumor of childhood, is a highly malignant retinal tumor. Retinoblastoma results when a vulnerable retinal cell has a loss or inactivation of both alleles of the Rb1 gene on chromoso me 13q14. Tn most cases, retinoblastoma is readily diagnosed by clinical ex amination. For these patients, medical imaging with CT or MR is useful to d efine the intraocular extent of the tumor and to document orbital and intra cranial involvement. CT and MR are very useful in confirming the diagnosis of retinoblastoma by excluding simulating lesions.